GAME & WILDLIFE CONSERVATION TRUST

Changes in upland bird numbers and distribution in the Berwyn Special Protection Area, North Wales

between 1983 and 2012

Philip Warren & David Baines

June 2012 (revised October 2012)

The Game & Wildlife Conservation Trust The Coach House Eggleston Hall Barnard Castle County Durham DL12 0AG Tel: (01833) 651936 E-mail: pwarren@gwct.org.uk

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Contents

Contents ........................................................................................................................................................ 2

Summary ....................................................................................................................................................... 3

Acknowledgements ....................................................................................................................................... 4

Introduction .................................................................................................................................................. 5

Methods ........................................................................................................................................................ 8

Study area ................................................................................................................................................. 8

Data sources .............................................................................................................................................. 9

Red grouse surveys ................................................................................................................................... 9

Upland bird surveys ................................................................................................................................ 10

Analyses .................................................................................................................................................. 11

Results ......................................................................................................................................................... 12

Red grouse .............................................................................................................................................. 12

Upland bird surveys ................................................................................................................................ 18

Breeding waders ................................................................................................................................. 18

Passerines ........................................................................................................................................... 21

Corvids ................................................................................................................................................ 23

Raptors ................................................................................................................................................ 25

Gamebirds ........................................................................................................................................... 27

Changes in the ranked abundance of birds in the Berwyn ..................................................................... 29

Trends in relation to conservation status ............................................................................................... 29

Discussion.................................................................................................................................................... 31

References .................................................................................................................................................. 34

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Summary

The Berwyn Special Protection Area (SPA) supports the most extensive tract of blanket bog and

upland heath in Wales. The site was designated in 1998 as an SPA for its internationally

significant numbers of hen harrier Circus cyaneus, merlin Falco columbarius, peregrine Falco

peregrinus and red kite Milvus milvus, whilst also supporting significant proportions of Welsh

populations of upland breeding waders. Following the Second World War there has been a

decline in grouse moor management in the Berwyn and by the late 1990s driven grouse

shooting had ceased. In this report, we assess changes in the numbers of red grouse and the

abundance of other upland birds in the Berwyn using shooting bag records, grouse count data

collected on four moors between 1995 and 2012; and repeat upland bird surveys in 1983-5 and

2002.

Main findings Between 1983-5 and 2002, lapwing were lost from the Berwyn survey areas, golden

plover declined from 10 birds to one and curlew declined by 79% despite its

conservation designations.

Carrion crow numbers increased six-fold and raven four-fold, with the number of

occupied 1-km2 grid squares doubling and trebling respectively.

Buzzard numbers increased two-fold in abundance and the number of occupied grid

squares increased four-fold. Peregrines also increased seven-fold in abundance,

whilst hen harriers declined by half. There were no significant changes detected in the

abundance of the other SPA designated raptors, merlin and red kite.

Meadow pipits and whinchat doubled and stonechat increased ten-fold between

surveys. Ring ouzel declined by 78% and tree pipit by 50%.

The numbers of red grouse shot in the Berwyn peaked in the early 1900s and then

declined, with driven grouse moor management having ceased by the late 1990s.

Between the upland breeding bird surveys, red grouse numbers declined by 54% and

the occupied range of 1-km2 grid squares fell by 38%.

Grouse count data on four moors collected since 1995 showed that grouse numbers

have remained at low levels on three of the moors, with adult summer densities at

Llanarmon declining from 15 grouse km-2 in 1995 to 3 grouse km-2 in 2009. Summer

densities ranging from 21 grouse km-2 at Llanarmon to 6 grouse km-2 at Vyrnwy.

For black grouse, numbers declined by 78% between the upland breeding bird surveys

and occupied 1-km2 grid squares fell by 28%.

To restore breeding wader populations within the Berwyn, we recommend that

predator control is incorporated as a general tool within agri-environment schemes,

particularly where habitat enhancements through heather burning and appropriate

grazing are being practised.

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Acknowledgements

We would like to thank the Moorland Association for funding this study. We would also like to

thank the Countryside Council for Wales (CCW) for providing data from the upland bird surveys

undertaken in the Berwyn in 1983-5 and 2002 and to the numerous fieldworkers from CCW and

RSPB who completed the survey work. We would also like to thank all the landowners for

allowing us access to their land to undertake grouse counts in spring and summer and to the

RSPB for providing grouse count data from Vyrnwy. Thanks also to Julie Ewald, Neville Kingdom

and Christopher Wheatley who gave valuable assistance with GIS related issues and to Nicholas

Aebischer for providing National Gamebag Census data for moors within the Berwyn.

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Introduction

Heather Calluna vulgaris dominated moorland in the uplands of the United Kingdom is of high

international conservation importance for a range of birds species (Thompson et al. 1995). In

Wales, the Berwyn is the most important upland area for breeding birds and was designated as

a Special Protection Area (SPA) in accordance with the European Union Birds Directive (EEC

1979) in 1998 to protect the internationally significant populations of hen harrier Circus

cyaneus, merlin Falco columbarius, peregrine Falco peregrinus and red kite Milvus milvus (Table

1). The Berwyn also supports significant proportions of the Welsh populations of other upland

birds and is designated as a Site of Special Scientific Interest (SSSI) for its upland breeding bird

assemblage, which includes black grouse Tetrao tetrix, red grouse Lagopus lagopus scoticus,

golden plover Pluvialis apricaria, dunlin Calidris alpina, snipe Gallinago gallinago, curlew

Numenius arquata, short-eared owl Asio flammeus, whinchat Saxicola rubetra, stonechat

Saxicola torquata, wheatear Oenanthe oenanthe, ring ouzel Turdus torquatus, raven Corvus

corax and chough Pyrrhocorax pyrrhocorax.

Table 1. Performance indicators for breeding population size for the four raptor species, hen harrier,

merlin, peregrine and red kite which the Berwyn is designated (Source: Berwyn SPA core management

plan, 2008).

Species

Targets

Hen Harrier 14 pairs representing at least 2.8% of the breeding population in Great Britain (5 year mean, 1991-1995)

Merlin 14 pairs representing at least 1.1% of the breeding population in Great Britain (5 year mean, 1991-1995)

Peregrine 18 pairs representing at least 1.5% of the breeding population in Great Britain (5 year mean, 1991-1995)

Red Kite 2 pairs representing at least 1.2% of the breeding population in Great Britain (5 year mean, 1991-1995)

The Berwyn Special Protection Area (SPA) is an extensive area of heather moorland running

south west from Llangollen in the north east to Mallwyd in the south west covering 241.8 km2

(Figure 1). Habitats in the Berwyn grade from the ffridd (upland fringes) on the lower slopes

(300m) through acid grassland, dry heath up to blanket bog on the higher areas (830m). The

area supports the most extensive tract of blanket bog in Wales, which is dominated by National

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Vegetation Classification (NVC) type M19 Calluna vulgaris- cotton grass Eriophorum vaginatum

blanket mire. It also contains the largest stand of upland European dry heath, which consists

principally of NVC type H12 Calluna vulgaris- bilberry Vaccinium myrtillus heath (Berwyn SPA

core management plan, 2008).

Figure 1. Location of the Berwyn Special Protection Area (SPA) in Wales

Following the Second World War, 46% of heather moorland in Wales (Lovegrove et al. 1995)

and 39% of heather moorland in the Berwyn has been lost due to overgrazing by sheep and

commercial afforestation (Berwyn SPA core management plan, 2008). Similarly, there has been

a decline in moorland management for red grouse shooting, where moorland gamekeepers are

employed to burn heather and control predators to produce harvestable surpluses for driven

shooting (Hudson 1992), with none of the moorland in the Berwyn now managed as driven

grouse moor. In the Berwyn SPA, some two thirds of the moorland is managed as a nature

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reserve by Severn Trent Water/ Royal Society for the Protection of Birds at Vyrnwy and by the

Countryside Council for Wales (CCW) at Pale. On the remaining moors, the less intensive

walked-up grouse shooting is now only practised (Sotherton et al. 2009). In this study we

assess the changes in the abundance of red grouse and a suite of other upland breeding birds in

the Berwyn SPA from red grouse shooting bag records, grouse counts conducted on 16, 1-km2

blocks on four moors between 1995 and 2012 and from a repeat upland bird survey across 107,

1-km2 grid squares in 1983-5 and 2002 (Sim et al. 2005).

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Methods

Study area

The Berwyn covers 241.8 km2 of upland North Wales, designated as a SPA, SSSI and a Special

Area of Conservation (SAC). The largest landholding here is the 100.8 km2 Severn Trent Water/

RSPB Vyrnwy Estate, which includes 42 km2 of the Berwyn National Nature Reserve (NNR)

(Figure 2). The second largest holding is the 38 km2 Pale Moor NNR managed by CCW. The

remainder of the Berwyn SPA is managed privately, with the main landholdings being the

Llanarmon Estate covering 31.4 km2 and the Carrog (5.8 km2), Nantyr (9.4 km2) and Vivod (7.0

km2) estates. Grouse count data were also available from Ruabon, which although not within

the Berwyn SPA were included in the analyses as the moor lies adjacent to the north east

(Figure 2) and is within the same SAC.

Figure 2. Distribution of the main landholdings within the Berwyn SPA

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Data sources

Upland bird survey data from the Berwyn SPA in 1983-5 and 2002 were sourced under licence

from Countryside Council for Wales (CCW). Red grouse bag data were extracted from the

GWCT’s National Gamebag Census (NGC) which collects shooting bag returns annually from

over 600 estates in the UK (Tapper 1992) for moors with returns from the Berwyn. Red grouse

count data between 1995 and 2000 were collected as part of The Welsh Grouse Project, a

partnership project between GWCT, CCW and RSPB. Subsequent grouse counts were

undertaken on Llanarmon, Pale and Ruabon periodically by GWCT and by the RSPB at Vyrnwy.

Red grouse surveys

Red grouse were surveyed using pointing dogs pre-breeding in spring (March and April) and

post-breeding in summer (July and August) within 1-km2 blocks on four moors; Vyrnwy,

Ruabon, Pale and Llanarmon (Figure 2). Surveys commenced in 1995 with red grouse surveyed

within two 1-km2 count areas at Ruabon; six at Pale; six at Vyrnwy and two at Llanarmon. All

four moors were surveyed in summer up until 2000 (Table 2). Then, surveys have been

undertaken less frequently, with Vyrnwy surveyed the most regularly (in seven of the 11 years).

Table 2. Red grouse surveys undertaken in spring and summer on four moors, Vyrnwy, Ruabon, Pale

and Llanarmon in the Berwyn 1985-2012

Moor Pale Llanarmon Ruabon Vyrnwy Year Spring Summer Spring Summer Spring Summer Spring Summer

1995 √ √ √ √ √ √ √ √ 1996 √ √ √ √ √ √ √ 1997 √ √ √ √ √ √ √ √ 1998 √ √ √ √ √ √ √ √ 1999 √ √ √ √ √ √ 2000 √ √ √ √ √ 2001 √ 2002 √ √ √ √ 2003 √ √ √ √ 2004 √ √ √ √ 2005 2006 √ √ 2007 √ √ √ √ 2008 √ √ 2009 √ √ √ √ √ 2010 √ √ 2011 2012 √ √

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Upland bird surveys

We assessed upland bird survey data collected in the Berwyn SPA within 107, 1-km2 grid

squares (Figure 3) grouped by CCW/RSPB into 14 plots for reporting purposes which were

surveyed in 1983-5 and then again in 2002. In 1983, 22, 1-km2 squares were surveyed, with a

further 52 in 1984 and 33 in 1985, with all repeated in 2002. Parallel line transects were walked

across the study plots with two observers spaced at 200m apart. Surveys were undertaken

between 08.30 and 18.00 hours BST to avoid the main periods of rapidly changing bird activity

(Reed et al. 1985). All bird sightings were mapped on to 1:10000 or 1:25000 maps using

standard behaviour codes. Surveys were not carried out in high winds greater than 35

km/hour, heavy rain or poor visibility. Repeat surveys in 2002 were undertaken within seven

days of the original survey dates with all surveyors received training in the survey technique

used to allow comparability between surveys (Sim et al. 2005).

Figure 3. Location of the upland bird survey 1-km2 squares in the Berwyn SPA surveyed in 1983-5 and repeated in 2002

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Analyses

Differences in red grouse spring and summer densities and breeding productivity between

moors and years were tested using ANOVA. Changes in red grouse abundance in spring and

summer between 1995 and 2012 were assessed using linear regression. Data were not

available from counts in spring and summer on all moors in all years (Table 2) therefore to

assess whether red grouse populations were in decline or were just at different stages within a

natural cycle (Hudson 1992) we increased the sample size by calculating adult summer densities

for those years with only spring count data available. Adult summer densities were estimated

through calculating a mean breeding season loss rate (change in numbers of adults between

spring and summer counts) calculated from all moors where spring and summer data were

available.

The analyses of breeding bird abundance were based on the maximum count from one of the

two visits. Counts of flocks of waders (five or more) were excluded. We tested for significant

differences only where the measure abundance was 30 or more in either the original or repeat

survey. We assessed changes in the numbers of breeding birds between surveys in 1983-85

and 2002 using Generalised Linear Models (GLM) with a Poisson error distribution and a

logarithm link function in Genstat 11 (VSN international Ltd). All birds were counted in both

survey years, with the exception of skylark and meadow pipit which were only counted across

both periods in six of the 14 study plots.

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Results

Red grouse

National Gamebag Census

Long term red grouse bag data were available from four moors in the Berwyn 1880-2010. In

the early 1900s the numbers of red grouse shot peaked on one moor at 282 grouse shot km-2

but then subsequently declined (Figure 4), with little shooting during the Second World War.

Following the Second World War the numbers shot increased on three of the moors, peaking in

the 1970s at 82 grouse km-2 but by the early 1990s grouse were infrequently shot on all four

moors.

Figure 4. Numbers of red grouse shot km-2 on four moors in the Berwyn 1880-2010

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In 1994, a survey to establish the extent and management of grouse moors in Wales (CCW

unpublished report) identified ten grouse moors in the Berwyn, with data available for nine.

Gamekeepers were employed on five moors (four part-time and one full-time), with the other

four unkeepered. Two moors shot driven grouse, five shot grouse walked up, whilst grouse

were no longer shot on the remaining two moors. By the late 1990s, driven grouse moor

management in the Berwyn had effectively ceased (Offord 2002, Whitfield & Fielding 2009).

Pre-breeding densities

Between 1995 and 2012, spring densities of red grouse differed between the four moors

Llanarmon, Pale, Ruabon and Vyrnwy (F3,14= 13.2, P<0.001) but not between years (F14,14=2.34,

P=0.06) (Table 3). Average spring densities at Llanarmon (15.8 grouse km-2) and Ruabon (16.1

grouse km-2) were four-fold higher than at Vyrnwy (4.2 grouse km-2) and just over double that

at Pale (6.7 grouse km-2).

Table 3. Average spring and summer densities and breeding productivity recorded on the four moors,

Llanarmon, Pale, Ruabon and Vyrnwy in the Berwyn SPA between 1995 and 2012

Moor Mean spring density (grouse km-2 +1SE)

Mean summer density (grouse km-2 +1SE)

Breeding productivity (chicks per hen +1SE)

Llanarmon 15.8 (4.8) 20.6 (3.2) 2.7 (0.5)

Pale 6.7 (0.9) 9.4 (2.6) 2.5 (0.4) Ruabon 16.1 (2.4) 15.5 (3.2) 3.0 (0.6)

Vyrnwy 4.2 (0.4) 5.9 (2.3) 2.5 (0.4)

Between 1995 and 2012, red grouse densities in spring on three of the four moors, Ruabon

(slope= -0.32, r2=0.14, P=0.46), Pale (slope= 0.18, r2=0.10, P=0.38) and Vyrnwy (slope= -0.15,

r2=0.29, P=0.09) remained at low levels, with no evidence of any trend (Figure 5). At

Llanarmon, spring densities declined from 32.5 grouse km-2 in 1995 to 5 in 2007 but the decline

was not statistically significant (slope= -1.43, r2=0.41, P=0.24) (Figure 5a).

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Figure 5. Red grouse spring densities (grouse km-2) on the four moors, Llanarmon, Pale, Ruabon and

Vyrnwy in the Berwyn SPA between 1995 and 2012

(a) Llanarmon (b) Pale

(c) Ruabon (d) Vyrnwy

Post-breeding densities

Summer densities of red grouse differed between moors (F3,14= 4.9, P=0.009) but not between

years (F13,23=1.9, P=0.08). Average summer densities ranged from 20.6 grouse km-2 at

Llanarmon to 5.9 (+.2.3SE) grouse km-2 at Vyrnwy (Table 3). There were no trends in summer

densities between 1995 and 2011 at Ruabon (slope= -0.91, r2=0.24, P=0.13), Pale (slope= -0.32,

r2=0.00, P=0.56) or Vyrnwy (slope= -0.33, r2=0.14, P=0.12) (Figure 6). At Llanarmon, summer

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densities declined from 59.5 grouse km-2 in 1995 to 8 in 2009, but the decline was not

statistically significant (slope= -2.32, r2=0.47, P=0.06) (Figure 6a).

Figure 6. Red grouse summer densities (grouse km-2) on the four moors Llanarmon, Pale, Ruabon and

Vyrnwy in the Berwyn SPA between 1995 and 2011

(a) Llanarmon (b) Pale

(c) Ruabon (d) Vyrnwy

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Breeding productivity did not differ between moors (F3,22=0.23, P=0.87) or years (F13,23=1.6,

P=0.15). Breeding productivity ranged from 0.7 chicks per hen in 2003 to 4.6 in 2008 (Figure 7).

Figure 7. Red grouse breeding productivity (mean chicks per hen (+1SE)) from four moors Llanarmon,

Vyrnwy, Pale and Ruabon in the Berwyn SPA between 1995 and 2010 (No data were collected in 2001

due to a Foot and Mouth Disease outbreak)

Adult summer density

Adult summer densities differed between moors (F3,24=10.62, P<0.001) and years (F15,24=3.13,

P=0.006). No trends were evident at Pale (slope=-0.06, r2=0.02, P=0.69), Ruabon (slope=-0.31,

r2=0.23, P=0.19) or Vyrnwy (slope=-0.85, r2=0.88, P=0.07) (Figure 8). Cycling was evident at Pale

(Figure 8b) and Vyrnwy (Figure 8d). At Llanarmon, adult summer densities declined from 15

birds km-2 in 1995 to 3 in 2009 (slope=-0.85, r2=0.88, P<0.001) (Figure 8a).

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Figure 8. Red grouse adult summer densities (grouse km-2) on the four moors Llanarmon, Pale,

Ruabon and Vyrnwy in the Berwyn SPA between 1995 and 2012

(a) Llanarmon (b) Pale

(c) Ruabon (d) Vyrnwy

y = -0.8529x + 14.412 R² = 0.885

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Upland bird surveys

Breeding waders

In 1983-85, lapwing were present, albeit in low numbers (14 birds) (Table 4) found within 10, 1-

km2 grid squares (Table 5, Figure 9a) but in the repeat survey in 2002 lapwing were absent.

Similarly, in 1983-85 a maximum of 10 golden plover were recorded over the two counts

observed within 11, 1-km2 grid squares, but in 2002 only one bird was observed (Figure 9b).

Curlew declined by 79% between survey years from 148 (1.38 birds km-2) to 31 (0.29 birds km-2)

with occupied range contracting by 75% (Table 5) (Figure 9c). Snipe were present in both

surveys albeit at low density. The abundance of all breeding waders combined declined by 80%

between survey years.

Table 4. The total numbers and density of breeding waders (birds km-2) in the Berwyn SPA survey

areas in 1983-5 and 2002 and the changes in abundance between survey years

Species Total number (density - birds km-2) Change (%) F1,27 P

1983-5 2002

Lapwing 14 (0.13) 0 (0) -100

Curlew 148 (1.38) 31 (0.29) -79 83.14 <0.001

Golden plover 10 (0.09) 1 (0.01) -90

Snipe 9 (0.08) 4 (0.05) -44

All waders 181 (1.69) 36 (0.35) -80 105.82 <0.001

Table 5. Changes in the distribution (presence within 1-km2 squares) of breeding waders in the

Berwyn SPA between 1983-5 and 2002

1-km2 grid squares observed

1983-5 2002 % change

Lapwing 10 0 -100

Curlew 68 17 -75

Golden Plover 11 1 -91

Snipe 8 5 -38

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Figure 9. Distribution of breeding waders in 1983-5 and in 2002 in the Berwyn SPA (filled 1-km2 squares denotes presence, open squares absence). (a) Lapwing

1983-5 2002

(b) Golden plover

1983-85 2002

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(c) Curlew

1983-85 2002

(d) Snipe

1983-5 2002

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Passerines

Moorland specialists

Between the surveys in 1983-5 and 2002 the numbers of meadow pipits Anthus pratensis and

whinchat doubled and stonechat increased ten-fold (Table 6). The occupied range of meadow

pipits remained unchanged, whilst whinchat increased by 50% from 42 to 63 occupied 1-km2

grid squares and stonechat by 700% from six to 48 grid squares (Table 7). There were no

significant changes in the numbers or distribution of skylark Alauda arvensis or wheatear

between survey years. Ring ouzel declined by 78% and tree pipit Anthus trivialis by 50%

between surveys.

Other passerines

Between survey years wren Troglodytes troglodytes increased eightfold and there were

increases in the numbers of summer visiting willow warbler Phylloscopus trochilus (+145%),

whitethroat Sylvia communis (+900%), grasshopper warbler Locustella naevia (+100%) and

chiffchaff Phylloscopus collybita (+471%) (Table 6). Woodpigeon Columba palumbus increased

from two (0.02 birds km-2) in 1983-5 to 45 (0.42 birds km-2) in 2002. Overall the densities of all

passerines combined doubled between survey years.

Table 6. The total numbers and density of passerines in the Berwyn SPA survey areas in 1983-5 and

2002 and the changes in abundance between survey years (*skylark and meadow pipit were only

surveyed in six plots across both survey years)

Species Total numbers (density- birds km-2) Change (%) F1,27 P

1983-5 2002

Skylark* 53 (1.02) 63 (1.21) +19 0.86 0.35

Meadow pipit* 602 (11.58) 1220 (23.46) +103 213.83 <0.001

Whinchat 84 (0.79) 187 (1.75) +122 40.15 <0.001

Stonechat 7 (0.07) 76 (0.71) +914 67.05 <0.001

Wheatear 25 (0.23) 24 (0.22) -4

Ring ouzel 10 (0.09) 2 (0.02) -78

Tree pipit 107 (0.40) 21 (0.20) -50 7.72 0.005

Wren 16 (0.15) 133 (1.24) +727 104.94 <0.001

Willow warbler 31 (0.29) 76 (0.71) +145 19.53 <0.001

Whitethroat 2 (0.02) 22 (0.20) +900

Grasshopper warbler 0 (0) 10 (0.09) +100

Woodpigeon 2 (0.02) 45 (0.42) +2000 48.52 <0.001

Cuckoo 11 (0.10) 5 (0.05) -50

Chiffchaff 8 (0.07) 43 (0.40) +471 26.39 <0.001

Linnet 29 (0.27) 38 (0.36) +33 1.21 0.27

All passerines (15.1) (31.04) +120 384.57 <0.001

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Table 7. Changes in the distribution (presence within 1-km2 squares) of passerines in the Berwyn SPA

between 1983-5 and 2002

Species 1-km2 grid squares observed

1983-5 2002 % change

Skylark* 49 (52) 51 (52) +4 Meadow pipit* 49 (52) 50 (52) +2 Whinchat 42 63 +50 Stonechat 6 48 +700 Wheatear 20 12 -40 Ring ouzel 7 2 -71 Tree pipit 24 16 -33 Wren 15 55 +267 Willow warbler 16 26 +63 Whitethroat 2 13 +550 Grasshopper warbler 0 6 +100 Woodpigeon 1 10 +900 Cuckoo 10 6 -40 Chiffchaff 7 21 +200 Linnet 4 14 +250

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Corvids

Carrion crow Corvus corone increased six-fold from 49 (0.46 birds km-2) to 308 (2.88 birds km-2 )

between 1983-5 and 2002 (Table 8) with their occupied range doubling from 26 to 61, occupied

1- km2 grid squares (Table 9, Figure 10a). Raven Corvus corax also increased four-fold from 12

(0.11 birds km-2) to 49 (0.46 birds km-2) with their occupied range trebling from 11 to 32

occupied 1-km2 squares (Table 9, Figure 10b). Jackdaw Corvus monedula also increased in

density from one (0.01 birds km-2) in 1983-5 to 21 (0.21 birds km-2) in 2002. All corvids

combined increased six-fold between survey years.

Table 8. The total numbers and density of corvids in the Berwyn SPA survey areas in 1983-5 and 2002

and the changes in abundance between survey years

Species Total numbers (density - birds km-2) Change (%) F1,27 P

1983-5 2002

Raven 12 (0.11) 49 (0.46) +318 24.07 <0.001

Carrion crow 49 (0.46) 308 (2.88) +526 209.35 <0.001

Jackdaw 1 (0.01) 23 (0.21) +2000

All corvids 62 (0.58) 380 (3.55) +512 254.33 <0.001

Table 9. Changes in the distribution (presence within 1-km2 squares) of corvids in the Berwyn SPA

between 1983-5 and 2002

1-km2 grid squares observed

1983-5 2002 % change

Carrion crow 26 61 +135

Raven 11 32 +191 Jackdaw 1 1 0

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Figure 10. Distribution of the corvids, carrion crow and raven in 1983-5 and in 2002 in the Berwyn SPA (filled 1-km2 squares denotes presence, open squares absence).

(a) Carrion crow

1983-5 2002

(b) Raven

1983-5 2002

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Raptors

Buzzard Buteo buteo increased two-fold from 14 (0.13 birds km-2) to 27 (0.33 birds km-2)

between 1983-5 and 2002 (Table 10), with their occupied range increasing four-fold from nine

to 37, 1-km2 grid squares (Table 11, Figure 11). Peregrines also increased seven-fold from one

(0.01 birds km-2) to seven birds (0.07 birds km-2) and range increased from one to eight

occupied 1-km2 grid squares (Table 11). Hen harrier declined by 48% from 35 to 18 birds.

There were no significant changes detected in the abundance of the other raptors, merlin, red

kite, short eared owl, goshawk Accipter gentilis or kestrel Falco tinnunculus. There were no

significant changes in the abundance of all raptors combined between surveys.

Table 10. The total numbers and density of raptors in the Berwyn SPA survey areas in 1983-5 and

2002 and the changes in abundance between survey years

Species Total numbers (density- birds km-2) Change (%) F1,27 P

1983-5 2002

Hen harrier 35 (0.33) 18 (0.17) -48 -1.18 0.24

Merlin 10 (0.09) 14 (0.13) +44

Red Kite 2 (0.02) 4 (0.04) +100

Peregrine 1 (0.01) 8 (0.07) +600

Buzzard 14 (0.13) 35 (0.33) +154 9.30 0.002

Short-eared owl 3 (0.03) 2 (0.02) -33

Kestrel 18 (0.17) 15(0.14) -18

Goshawk 0 (0) 2 (0.02) +100

All raptors 83 (0.78) 98 (0.92) +18 1.24 0.27

Table 11. Changes in the distribution (presence within 1-km2 squares) of upland birds between 1983-5

and 2002 in the Berwyn SPA

1-km2 grid squares observed

1983-5 2002 % change

Hen Harrier 21 19 -10

Merlin 10 11 +10 Red Kite 2 4 +100

Peregrine 1 8 +700 Buzzard 9 37 +311 Short-eared owl 3 1 -67

Kestrel 19 15 -21 Goshawk 0 3 +100

26

Figure 11. Distribution of buzzards in 1983-5 and in 2002 in the Berwyn SPA (filled 1-km2 squares denotes presence, open squares absence).

1983-5 2002

27

Gamebirds

The numbers of red grouse and black grouse encountered on the upland breeding bird surveys declined by 54% and 78% respectively between survey years (Table 12). Occupied range of red grouse declined by 38% from 52 to 32 occupied 1-km2 grid squares and black grouse by 28% from 25 to 18 occupied squares (Table 13, Figure 12a). The abundance of all game birds combined declined by 63% between survey years. Table 12. The total numbers and density of gamebirds in the Berwyn SPA survey areas in 1983-5 and

2002 and the changes in abundance between survey years

Species Total number (density - birds km-2) Change (%) F1,27 P

1983-5 2002

Red grouse 117 (1.09) 54 (0.50) -54 23.77 <0.001

Black grouse 111 (1.04) 25 (0.23) -78 58.76 <0.001

Pheasant 7 (0.07) 10 (0.09) +29

All gamebirds 235 (2.20) 89 (0.82) -63 68.22 <0.001

Table 13. Changes in the distribution (presence within 1-km2 squares) of gamebirds in the Berwyn SPA

between 1983-5 and 2002

1-km2 grid squares observed

1983-5 2002 % change

Red grouse 52 32 -38 Black grouse 25 18 -28

Pheasant 6 8

28

Figure 12. Distribution of red grouse and black grouse in 1983-5 and in 2002 in the Berwyn SPA (filled 1-km2 squares denotes presence, open squares absence). (a) Red grouse

1983-5 2002

(b) Black grouse

1983-5 2002

29

Changes in the ranked abundance of birds in the Berwyn

Between survey years meadow pipit remained the most abundant bird within the Berwyn

(Table 14). In 1983-5 curlew were the second most abundant bird species but by 2002 they had

dropped down to fourteenth, red grouse dropped from third to eighth, and black grouse, tree

pipit and hen harrier all dropped out of the top ten. In 2002, carrion crow moved up to third

from seventh, with stonechat, raven and woodpigeon all moving up.

Table 14. The ranked abundance of birds in the Berwyn SPA recorded on upland bird surveys in 1983-

5 in relation to 2002

Rank 1983-5 2002

1 Meadow pipit Meadow pipit 2 Curlew Skylark 3 Red grouse Carrion crow 4 Skylark Whinchat 5 Black grouse Wren 6 Whinchat Stonechat 7 Carrion crow Willow warbler 8 Tree pipit Red grouse 9 Hen harrier Raven 10 Willow warbler Woodpigeon

Trends in relation to conservation status

Between 1983-5 and 2002 two thirds of Red-listed species (those which are globally threatened

according to International Union for Conservation of Nature and Natural Resources (IUCN)

criteria) declined in abundance in the Berwyn SPA (Table 15). Short-eared owl and kestrel

remained stable whilst there were increases in the numbers of willow warbler and grasshopper

warbler.

30

Table 15. Trends in numbers of birds within the Berwyn SPA in relation to their conservation status in

Wales (Johnstone et al. 2011)

Trend Conservation status in Wales RED AMBER GREEN

Decreasing Lapwing Tree pipit Curlew Golden plover Ring ouzel Black grouse Red grouse Cuckoo Stable Short-eared owl Red kite Hen harrier Merlin Kestrel Snipe Skylark Wheatear Increasing Willow warbler Meadow pipit Whinchat Grasshopper warbler Whitethroat Stonechat Wren Raven Carrion crow Jackdaw Peregrine Woodpigeon Buzzard

31

Discussion

Grouse moor management effectively ceased within the Berwyn SPA in the 1990s. Red grouse

remain at low densities, with shooting now restricted to walked-up shooting in good breeding

years (Sotherton et al. 2009). In comparison to other areas of the UK where red grouse

management persists, numbers of red grouse in Wales are now low and are considered

critically endangered following a rapid decline in range and abundance (Johnstone et al. 2011).

For purposes of comparison, from a sample of 43 moors in northern England between 1990 and

2011 red grouse summer densities were on average 177 grouse km-2 and in 2011 summer

densities were the highest recorded in the past thirty years with 318 grouse km-2 reported

(Baines et al. 2011).

With the cessation of grouse moor management in the Berwyn the assemblage of breeding

waders declined, lapwing were absent in the surveyed areas in 2002, golden plover declined to

one individual and curlew declined by 79% despite the high levels of conservation designation

given to the area. Whilst the breeding waders declined in the Berwyn SPA, the corvids; carrion

crow and raven flourished, with increases also in the raptors; buzzard and peregrine. The

increasing trend in numbers of raptors in the Berwyn reflects a wider UK trend, with buzzards

increasing by 435% between 1970 and 2010 and peregrine by 194% between 1970 and 2002

(Eaton et al. 2011) recovering from the legacy of organochlorine pesticides and historical

persecution (Banks et al. 2002). Similar changes in bird assemblages were observed following

the cessation of driven grouse moor management on a Scottish moor within a Scottish SPA

(Baines et al. 2008). On this moor, in the absence of gamekeepering, carrion crow and red fox

Vulpes vulpes abundance increased, whilst, when managed previously for driven shooting, red

grouse, curlew, lapwing, golden plover, skylark and hen harrier were all more abundant.

Breeding waders are declining throughout the British uplands (Sim et al. 2005) attributed to

commercial afforestation, drainage, increases in generalist predators, changes in grazing

patterns and a decline in grouse moor management. Grouse moors form an important refuge

for breeding waders. A survey of upland breeding birds in parts of England and Scotland found

that the densities of golden plover, curlew, redshank and lapwing were up to five-fold greater

on managed grouse moors compared to unmanaged moorland (Tharme et al. 2001). The rates

of decline observed in breeding waders in the Berwyn are of conservation concern, and it is

likely that in the coming decades, lapwing, golden plover and curlew will be lost from the Welsh

uplands unless urgent conservation management is implemented. Measures to prevent their

loss from these areas are required now as these birds demonstrate philopatry to breeding

grounds and have high site fidelity in breeding adults (Thompson et al. 1995, Pearce Higgins &

Yalden 2003, Grant et al. 1999). Therefore, if lost as a breeding species it is unknown if even if

conditions were improved whether birds would re-colonise because the nearest breeding

populations are 100 km to the east in the Peak District.

32

To restore breeding waders in the Berwyn SPA, control of the generalist predators, carrion crow

and red fox is recommended (Fletcher et al. 2010). In Northumberland, predator control

increased the breeding success and subsequent abundance of lapwing, curlew, golden plover

and red grouse, which in the absence of predator control failed to rear sufficient chicks to

sustain numbers which subsequently declined (Fletcher et al. 2010). Implementing predator

control alone in the Berwyn is likely to be ineffective, as habitats have also subtly changed.

Sheep grazing reductions to restore blanket bog habitats and the cessation of burning have

made the Berwyn less attractive to breeding waders. Similarly, the maturation of commercial

forest stands has also reduced the availability of habitats for moorland birds whilst providing

habitat for generalist predators. Evidence of these subtle changes in the vegetation from

managed heathland to unmanaged scrub can be deduced from the changes in the top ten

common birds encountered on upland bird surveys between 1983-5 and 2002. In 1983-5, six

species in the top ten were moorland and moorland fringe species; red grouse, curlew,

meadow pipit, hen harrier, skylark and black grouse, but in 2002, only three of these remained

with more scrub specialists, willow warbler and wren now occupying the top ten. Similarly

there were increases between survey years in whitethroat, grasshopper warbler and chiffchaff

all considered to be more scrub specialists than moorland birds. It is evident that to restore

the suite of upland waders to the Berwyn, both habitat management through burning and

grazing in conjunction with predator control would be required.

The Berwyn was designated as an SPA for hen harrier, merlin, peregrine and red kite. From the

repeat upland bird survey, peregrine increased whilst hen harrier declined. Over a similar

timeframe, more robust hen harrier monitoring within the Berwyn reported that numbers of

hen harrier increased from 5 pairs in 1983 to a peak of 18 territorial pairs in 1988, falling to 5

pairs in 2000 (Offord 2002). Since then numbers have recovered to 13 pairs in 2004, with a

wider recovery throughout Wales (Whitfield & Fielding 2009). Despite these increases, a report

on the status on the designated raptors concluded that the Berwyn SPA was considered to be in

unfavourable condition for these species as it had failed to meet targets for the numbers of

breeding pairs (Pathfinder Report 2008). Hen harriers prefer tall mature heather for nesting

(Redpath et al. 1998) and following a cessation in heather burning and reduced grazing this is

not deemed limiting in the Berwyn. Similarly, persecution stopped (Whitfield & Fielding 2009)

and a key prey species, meadow pipit (Amar et al. 2003) doubled in abundance between

surveys in 1983-5 and 2002. Therefore an increase in numbers may have been expected here.

Ground nesting raptors such as hen harrier and merlin are vulnerable to nest predation by foxes

(Baines et al. 2008). Therefore it is likely that predator control to increase breeding waders, in

the absence of illegal persecution would also be beneficial to these breeding raptors.

In the UK, breeding golden plover, dunlin, lapwing and curlew are disappearing from upland

areas (Sim et al. 2005), and grouse moors have been shown to support higher densities than

33

unmanaged moorland (Tharme et al. 2001, Tapper et al. 2005). In the Berwyn and wider Welsh

uplands no driven grouse shooting is now practised. The Berwyn has a history of producing

good grouse bags, but despite significant investment in heather moorland in northern England

and Scotland, this has not occurred in Wales. Restoring grouse moor management in Wales

would be difficult and very expensive due to a number and combination of factors which

include the fragmentation of heather habitats due to commercial afforestation, the presence of

the disease Louping ill, high densities of breeding raptors and heather burning restricted on

blanket bog. To restore breeding wader populations within the Berwyn, we suggest that

predator control is incorporated as a general tool within agri-environment schemes, particularly

where habitat enhancements through heather burning and appropriate grazing are being

practised.

34

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